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mru@users.sourceforge.net (Måns Rullgård) writes: > > > Btw, I just noticed that hard disk throughput is much lower with 2.5 > > > than 2.4. With 2.4.21-pre5 I get ~40 MB/s, but with 2.5.67 the speed > > > drops to 25-30 MB/s. Everything according to hdparm. Is it possible > > > that DMA is generally slow for some reason? > > > > Possible reason is that in 2.4 we've forced reasonable latency timer > > value for all PCI devices, while in 2.5 we haven't as yet. > > Do you mean whatever causes this message (for a 3com NIC)? > > PCI: Setting latency timer of device 00:05.0 to 64 > > Would that also explain why my hard disks are slow under 2.5? There > is no corresponding message for the ide controller (htp374). I just checked the troublesome board. Here's what lspci has to say: 00:06.0 Display controller: 3DLabs GLINT R3 (rev 01) Subsystem: 3DLabs: Unknown device 0121 Flags: bus master, 66Mhz, medium devsel, latency 0, IRQ 27 Memory at 0000000009020000 (32-bit, non-prefetchable) [size=128K] Memory at 000000000c000000 (32-bit, prefetchable) [size=64M] Memory at 0000000010000000 (32-bit, prefetchable) [size=64M] Expansion ROM at 0000000009060000 [disabled] [size=64K] Capabilities: <available only to root> The latency 0 doesn't look too good. What should I do to change it? -- Måns Rullgård mru@users.sf.net - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ | |||||||||
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